圆端形墩台尾迹水动力特性开缝控制三维数值分析

Three dimensional numerical analysis of hydrodynamic characteristics of circular pier and abutment wake with slit control

水流绕流水闸闸墩、导流墩等水工建筑物后产生旋涡分离流,其三维尾迹结构水动力特性复杂,对旋涡分离流进行流动控制,不仅是闸墩优化设计的需要,而且关系到工程运行的效率和工程安全。在验证三维水动力数学模型的基础上,对圆端形墩台开缝后的旋涡分离流和流动控制的三维水动力特性进行了研究,对比了无缝与开缝墩台方案下纵向、横向和竖向方向的时均流速分布,紊流动能以及紊流强度分布等水力学指标,探究了开缝墩台水动力特性。分析表明,墩台开缝后可以明显改善墩台后方的水流结构,开缝位置越靠近水深的中部位置,对墩后尾流旋涡的抑制越大,对绕流墩台绕流的控制越来越好,水深中部位置开缝最大程度的影响了开缝墩后的上部水流和下部水流,使得开缝对时均流速的影响最大,开缝对旋涡的抑制也最大最佳。为抑制墩后的旋涡对工程的不利影响,工程的设计中应首先确定墩台后的水深,开缝位置应尽量设置在墩台后水深的中部位置。

Water flows around hydraulic structures such as gate piers and diversion piers,it results in vortex separated flow.The three-dimensional wake structure has complex hydrodynamic characteristics,and flow control of vortex separated flow is not only necessary for the optimization design of gate piers,but also related to the efficiency and safety of engineering operation.On the basis of verifying the three-dimensional hydrodynamic mathematical model,this article studies the three-dimensional hydrodynamic characteristics of vortex separation flow and flow control after the circular end pier is slotted.It compares the time-averaged velocity distribution,turbulent flow energy,and turbulence intensity distribution in the longitudinal,transverse,and vertical directions under the seamless and slotted pier schemes,and explores the hydrodynamic characteristics of the slotted pier.Analysis shows that the water flow structure behind the pier can be significantly improved after the opening of the pier.The closer the opening position is to the middle of the water depth,the greater the suppression of the wake vortex behind the pier,and the better the control of the flow around the pier.The opening of the middle position of the water depth greatly affects the upper and lower water flow behind the slotted pier,making the opening the most influential on the time-averaged flow velocity,and the opening also has the greatest and best suppression on the vortex.To suppress the adverse effects of vortices behind the piers on the project,the water depth behind the piers and abutments should be determined first in the design of the project,and the opening position should be set as much as possible in the middle of the water depth behind the piers and abutments.